If your agency does not have a Amazon business account already in place before this pandemic, you are wasting you time. They have 125,000 applications and a team of 50 trying to vet them. Applications are increasing as individuals try to use it - which they will not allow. Its killing resources as they vet them out.
All government orders have to be with a .gov email, shipped to a government agency address verifiable with Google, have proper tax exempt paperwork on file and paid for by the agency.
In addition they are supposedly doing it "first come first serve" but it appears there is some favoring of federal orders.
Finally- even after you do all that - its like throwing out bird food to a flock of pigeons. They randomly update stuff and within minutes its gone. Have it in your cart and don't checkout fast enough and you will find your cart empty at checkout.
Better off making local contacts and getting supplies through hem.